Pharmacological and clinical evaluation of N4-beta-D-ribofuranosyltriazin-3-one-n1-oxide, (uricytin), which is a powerful inhibitor of mouse leukemias L-1210, P-388, and Adenocarcinoma-755, is proposed. The major objective of the studies will be to explore the possibility and scope of the drug for its ultimate use in clinic as a new antineoplastic agent at LAC/USC Cancer Hospital and Research Institute. Animal tumor models will be used to characterize schedule dependency and optimal schedules of therapy with uricytin, a C14-labeled synthesis of uricytin and some of its possible metabolites will be developed for studying drug metabolism and mechanism of action by usual methods as applied previously in related studies.